In German Patent Document DE-GM 8807118, there is described a dual container assembly for the purposes described in which the load-bearing outer container is fabricated from thermoplastic material while the inner container is comprised of a blown plastic foil or, as may be more generally referred to herein, plastic sheeting.
The outer container lid has an aperture which is of large caliber or diameter as compared with the diameter or caliber of the spigot, hereinafter referred to as an outlet pipe spigot, formed in the outer container near its base.
The spigot can have an external screwthread for receiving a cap or some other fixture capable of being connected to the container.
When the sack is filled, it conforms generally to the configuration of the outer container and is supported thereby.
In the container units of this kind described in DE-GM 8807118, large volumes are contemplated, i.e. the container unit may have a capacity of 1000 liters or more. The sack allows the outer container to be reused repeatedly in a simple manner and can be disposed of independently of the outer container so that any residues of the material within the inner container or sack can be retained therein for such disposal. Hence contamination of the environment or pollution from residues within the sack can be eliminated and disposal can be assured in accordance with applicable regulations and statutes.
Furthermore, when the inner container or sack is removed or disposed of with any residues, expensive cleaning or contamination of the interior of the outer container is not necessary. Of course, care must be taken to insure that the sack does not leak into the outer container after receiving the liquid or powder filling.
In a container unit as described in German patent Document DE-OS 22 55 299, the outer container is a barrel and the inner container is referred to as an insert bag and is connected to the bung in the barrel lid.
Experience has shown that this system has problems in tearing away of the insert bag from the bunghole and with the possibility that the contents of the container will be discharged into the interior of the barrel.
In a container of another type, namely, a folding container having a passage for the outlet spigot of the inner container (German patent document DE-AS 12 78 335), the inner bag has an outlet spigot disposed in the region at the top of the following container where it passes through the aperture formed at this location and is secured in place so that it can tear or pull away and release material into the outer container.